Method for populating a cache index on a deduplicated storage system

1. A method for populating an index cache on a deduplicated storage system, the method comprising: determining to flush an in-memory index to a hard drive (“HDD”) on the deduplicated storage system, wherein the in-memory index comprises a plurality of in-memory hash buckets, each in-memory hash bucket containing a plurality of fingerprints of a plurality of deduplicated segments and container identifiers identifying containers storing the deduplicated segments, wherein each of the in-memory hash buckets is identified by a hash bucket identifier that is generated by hashing each fingerprint stored in the corresponding in-memory hash bucket; loading a first HDD index from the HDD into a memory, wherein the first HDD index includes a plurality of HDD buckets; merging the fingerprints and the container identifiers from the in-memory hash buckets into the HDD buckets; mapping the HDD buckets to a plurality of solid state drive (“SSD”) buckets including determining a scaling factor between the HDD buckets and the SSD buckets, the SSD buckets together comprising a SSD index, wherein the SSD index is utilized to access deduplicated segments stored in an SSD device operating as a data cache device; and inserting the fingerprints and container identifiers into the plurality of SSD buckets.

2. The method of claim 1 , further comprising writing the HDD index back to the HDD.

3. The method of claim 1 , further comprising writing the SSD index to the SSD device.

4. The method of claim 1 , further comprising storing a lowest container identifier in the SSD buckets.

5. The method of claim 4 , wherein container identifiers stored in the SSD buckets comprise an offset from the lowest container identifier stored in the SSD buckets.

6. A system for populating an index cache on a deduplicated storage system, the system comprising a non-transitory computer readable medium and processor enabled to execute instructions for: determining to flush an in-memory index to a hard drive (“HDD”) on the deduplicated storage system, wherein the in-memory index comprises in-memory hash buckets, each in-memory hash bucket containing a plurality of fingerprints of a plurality of deduplicated segments and container identifiers identifying containers storing the deduplicated segments, wherein each of the in-memory hash buckets is identified by a hash bucket identifier that is generated by hashing each fingerprint stored in the corresponding in-memory hash bucket; loading a first HDD index from the HDD into a memory, wherein the first HDD index includes a plurality of HDD buckets; merging the fingerprints and the container identifiers from the in-memory hash buckets into the HDD buckets; mapping the HDD buckets to a plurality of solid state drive (“SSD”) buckets including determining a scaling factor between the HDD buckets and the SSD buckets, the SSD buckets together comprising a SSD index, wherein the SSD index is utilized to access deduplicated segments stored in an SSD device operating as a data cache device; and inserting the fingerprints and container identifiers into the plurality of SSD buckets.

7. The system of claim 6 , further comprising writing the HDD index back to the HDD.

8. The system of claim 6 , further comprising writing the SSD index to the SSD device.

9. The system of claim 6 , further comprising storing a lowest container identifier in the SSD buckets.

10. The system of claim 9 , wherein container identifiers stored in the SSD buckets comprise an offset from the lowest container identifier stored in the SSD buckets.

11. A non-transitory computer readable storage medium comprising processor instructions for populating an index cache on a deduplicated storage system, the instructions comprising: determining to flush an in-memory index to a hard drive (“HDD”) on the deduplicated storage system, wherein the in-memory index comprises in-memory hash buckets, each in-memory hash bucket containing a plurality of fingerprints of a plurality of deduplicated segments and container identifiers identifying containers storing the deduplicated segments, wherein each of the in-memory hash buckets is identified by a hash bucket identifier that is generated by hashing each fingerprint stored in the corresponding in-memory hash bucket; loading a first HDD index from the HDD into a memory, wherein the first HDD index includes a plurality of HDD buckets; merging the fingerprints and the container identifiers from the in-memory hash buckets into the HDD buckets; mapping the HDD buckets to a plurality of solid state drive (“SSD”) buckets including determining a scaling factor between the HDD buckets and the SSD buckets, the SSD buckets together comprising a SSD index, wherein the SSD index is utilized to access deduplicated segments stored in an SSD device operating as a data cache device; and inserting the fingerprints and container identifiers into the plurality of SSD buckets.

12. The computer readable storage medium of claim 11 , further comprising writing the HDD index back to the HDD.

13. The computer readable storage medium of claim 11 , further comprising writing the SSD index to the SSD device.

14. The computer readable storage medium of claim 11 , further comprising storing a lowest container identifier in the SSD buckets.

15. The computer readable storage medium of claim 14 , wherein container identifiers stored in the SSD buckets comprise an offset from the lowest container identifier stored in the SSD buckets.